Injection pump

ABSTRACT

A multi-diaphragm injection pump, having the driving diaphragm and the injection diaphragm joined together by means of a connecting rod so as that any movement of the driving diaphragm will result in an equal movement of the injection diaphragm, these two diaphragm being controlled by a mechanical micro-valve which is engaged by the connecting rod and therefore allows for the automatic actuation of the driving diaphragm which will drive the injection diaphragm which will cause any fluid to be drawn into the fluid chamber and then discharged at a higher pressure.

FIELD OF THE INVENTION

The present invention relates generally to the field of injection pumps, and more particularly to a multi-diaphragm pump for injecting chemicals into a pressurized process such as a gas well.

SUMMARY OF THE INVENTION

The present invention is directed to an injection pump comprising a pressure chamber, a driving diaphragm, a fluid chamber, an injection diaphragm, a connecting rod, and a control unit. The pressure chamber has an inlet port and the driving diaphragm is disposed in the pressure chamber. The fluid chamber comprises a fluid supply port connectable to a fluid source and an outlet port. The injection diaphragm is disposed in the fluid chamber. The connecting rod is operatively connected to the driving diaphragm and the injection diaphragm. The control unit operatively engages the connecting rod and is adapted to supply a pressurized fluid to the inlet port of the pressure chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a cross-section view of a pump built in accordance with the present invention.

FIG. 2 illustrates the pump of FIG. 1 in an exhaust mode.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Gas and oil well drilling and pumping operations are generally done under pressurized conditions. The production and transmission of oil and gas are also done under pressurized conditions. The pressurized processes frequently require chemicals be injected into the process for various reasons. Pumps are used for injecting chemicals or other fluids into the pressurized process. In certain operations for example, appropriate chemicals may be injected to a process for enhanced fluid expulsion or to neutralize corrosive situations. Alternatively, a chemical such as methanol may be required to keep fluids from freezing where pressure fluctuations cause significant temperature drops in fluid.

The present invention is directed to an improved pump for use in injecting chemicals to a pressurized process, such as a gas well application. The invention comprises a multi-diaphragm pump for high (approx. >100 psi) or very high pressure (approx. >1500 psi) applications. The pump provides fluid at a high pressure with a relatively small input pressure. The pump uses a larger driving diaphragm for the input and a smaller injection diaphragm, combined with a connecting shaft, to provide amplification of the input pressure. One skilled in the art will appreciate that relationship may be a function of the diameter of the driving diaphragm and the diameter of the connecting shaft. Preferably the ratio of a diameter of the driving diaphragm to the injection diaphragm is approximately 64:1. A preferred diameter for the driving diaphragm may be eight inches. The preferred diameter for the connecting shaft is one inch. Sealed fluid cavities at both diaphragms help to prevent corrosion and wear of the pump.

With reference now to the drawings and to FIG. 1 in particular, there is shown therein an injection pump built in accordance with the present invention. The pump, designated by reference numeral 10, comprises a pressure chamber 12 having a driving diaphragm 16 disposed therein and a fluid chamber 14 having an injection diaphragm 18 disposed therein. The diaphragms 16 and 18 are joined by a connecting rod 20. The connecting rod 20 is preferably disposed within a housing 22 that bridges the chambers 12 and 14. A control unit 24 is operatively connected to the connecting rod 20 and adapted to supply a pressurized fluid to the pressure chamber 12. The pump 10 may further comprise a pump stand 26 and a pump handle 28 for ease of use and handling.

The pressure chamber 12 comprises a casing 30 forming a chamber 32 and enclosing the driving diaphragm 16. The casing 30 comprises a diaphragm cover 34 and a pressure chamber base 36. The diaphragm cover 34 and chamber base 36 may be bolted together, forming the chamber 32. The driving diaphragm 16 is disposed in the chamber 32 and forms a sealed pressure cavity 38 in the chamber on a pressured side of the diaphragm. The pressure chamber 12 further comprises an inlet port 40 formed in the diaphragm cover 34. The inlet port 40 provides for a connection to a source of pressurized fluid, yet to be described. In operation, pressurized fluid will fill the sealed cavity 38 on the pressured side of the diaphragm 16.

The fluid chamber 14 comprises a fluid case 42 forming a chamber 44 and enclosing the injection diaphragm 18. The fluid case 42 comprises a fluid body cover 46 and a fluid base 48. The fluid body cover 46 and base 48 may be bolted together, forming the chamber 44. The injection diaphragm 18 is disposed in the chamber 44 and forms a sealed fluid cavity 50 on a pumping side of the injection diaphragm. The fluid chamber 14 further comprises a fluid supply port 52 and an outlet port 54 formed in the fluid body cover 46. The fluid supply port 52 is connectable to a fluid source (not shown) for the fluid to be injected by the pump 10 into the pressurized process (not shown). In the preferred embodiment, a suction check valve 55 is used to connect the supply port to the fluid source. The fluid enters the fluid chamber 14 through the supply port 52 into the fluid cavity 50. The outlet port 54 is operatively connected to the pressurized process. Fluid from the fluid cavity 50 is pumped from the cavity through the outlet port 54 to the pressurized process.

In the preferred embodiment, a connecting tee 56 is connected to the outlet port 54 of the fluid chamber 14. The connecting tee comprises a first outlet 58 and a second outlet 60. A discharge check valve 62 is connected to the first outlet 58 of the connecting tee 56. The discharge check valve 62 is further connected to the pressurized process. A priming valve 64 is preferably attached to the second outlet 60 of the connecting tee 56, to allow for further regulation of the flow of fluid to the pressurized process.

The connecting rod 20 is operatively connected to the driving diaphragm 16 and the injection diaphragm 18. The connecting rod 20 is preferably of rigid construction, formed of steel, iron or other suitable material. Preferably, flange bolts 66 and 67 may be used to secure the diaphragms 16 and 18 to the connecting rod 20. The connections between the connecting rod 20 and the diaphragms 16 and 18 are such that any movement in the driving diaphragm 16 will result in a coordinated movement in the injection diaphragm 18. The connecting rod 20 may be of any length appropriate for the size of the pump 10 and its application. A stroke length of the connecting rod 20 may also be selected as appropriate for the diaphragms 16 and 18 and the pump 10 application. In the preferred embodiment, the stroke length of the connecting rod 20 is ¼ inch.

A diaphragm plate 68 is used between the diaphragm 16 and the connecting rod 20 to provide a working diaphragm surface and support for the flange bolt 66 connection. The diaphragm plate 68 is preferably of a diameter that allows for a selected input ratio for the pump 10. In the preferred embodiment, the diameter of the plate 68 is eight inches, although the size of the plate is a design consideration. The connecting rod 20 also has a diameter that provides a working surface of the injection diaphragm 18 and is significant to the output of the pump 10. In the preferred embodiment, the diameter of the connecting rod 20 is one inch, although the diameter of the rod is a design consideration. Alternatively, a diaphragm plate 69 may be used to increase the working surface of the injection diaphragm 18.

The connecting rod 20 is preferably disposed in the housing 22. The housing 22 may be formed of cast iron or other like materials. The durable construction of the housing 22 provides protection for the connecting rod 20 from corrosion and wear inherent to use of the pump 10. The housing 22 further comprises at least one vent 70. The vent 70 allows for any fluid leaked into the housing 22 to be exhausted so that pressure does not build in the housing around the connecting rod 20.

The housing 22 is connected at a first end 72 to the pressure chamber 12 and at a second end 74 to the fluid chamber 14. Preferably, the housing 22 is connected to the pressure chamber base 36 of the pressure chamber 12 at the first end 72 of the housing, and to the fluid base 48 of the fluid chamber 14 at the second end 74 of the housing. The housing 22 may be welded or secured by other means. Alternatively, the housing 22 may be integrally formed with the pressure chamber base 36 of the pressure chamber 12 and the fluid base 48 of the fluid chamber 14.

A biasing spring 76 is preferably disposed around the connecting rod 20 and proximate the driving diaphragm 16. In the preferred embodiment, the spring 76 is disposed in the pressure chamber 12. The spring 76 is positioned between the diaphragm plate 68 and the pressure chamber base 36. Alternatively, where the housing 22 is integrally formed with the pressure chamber base 36, a ridge 78 or other surface may be provided in the housing 22 for the spring 76 to work on. The biasing spring 76 is preferably positioned to bias the diaphragms 16 and 18 and the connecting rod 20 in a relaxed state when the spring is extended. As shown in FIG. 1, and as to be further discussed below, when the diaphragms 16 and 18 are in the relaxed state the pump 10 will be in a supply mode. When the biasing spring 76 is compressed, as shown in FIG. 2 and as to be further discussed below, the pump 10 is in an exhaust mode where the pressure in the pressure chamber 12 has built causing the fluid in the fluid chamber 14 to be delivered to the pressurized process.

With reference again to FIG. 1, the control unit 24 is preferably positioned on the housing 22 and operatively connected to the connecting rod 20. The control unit 24 comprises a fluid inlet 80, a fluid supply port 82, and an exhaust valve 84. The fluid inlet 80 is connectable to a remote source of pressurized fluid (not shown). The fluid supply port 82 is operatively connected to the inlet port 40 of the pressure chamber. The exhaust valve 84 allows pressurized fluid to be released from the control unit 24. The control unit 24 functions to deliver pressurized fluid received from the source of pressurized fluid to the pressure chamber 12. In the preferred embodiment, the control unit 24 delivers pressurized air or gas. However, the pressurized fluid may alternatively be in liquid form.

The control unit 24 is further operatively connected to the connecting rod 20. The control unit 24 operates to sense the movement and position of the connecting rod 20 so that pressurized fluid is supplied to the pressure chamber 12 when the pump 10 is in a supply or inject mode. For sensing the position of the connecting rod 20, the control unit 24 may comprise a movable switching arm 86. The switching arm 86 is connected to the connecting rod 20 and indicates when the connecting rod is in the supply mode or the exhaust mode. A control unit 24 suitable for use with the present invention is available in the micro valve line of control valves available from Invalco, Inc.

Operation of the pump 10 is as follows. In the supply mode, there is a lack of pressure buildup or pressurized fluid in the sealed pressure cavity 38 of the pressure chamber 12. The spring 76 is extended and positions the diaphragms 16 and 18 and the connecting rod 20 in the biased or relaxed state as shown in FIG. 1. The positioning of the switch arm 86 of the control unit 24 causes the control unit to pass pressurized fluid to the pressure chamber 12. At substantially the same time, fluid is drawn into the fluid cavity 50 of the fluid chamber 14 through the suction check valve 55.

When the pressure level in the pressure cavity 38 of the pressure chamber 12 builds, the driving diaphragm 16 will move and the pump 10 will go to exhaust mode, as shown in FIG. 2. Movement of the driving diaphragm 16 will cause the spring 76 to compress and a resultant move by the connecting rod 20. Movement of the connecting rod 20 will consequently cause the injection diaphragm 18 to move. As the injection diaphragm 18 is moved, fluid in the fluid cavity 50 of the fluid chamber 14 will be discharged at pressure through the discharge check valve 62 and to the pressurized process.

In the exhaust mode, the switch arm 86 of the control unit 24 will be in the position shown in FIG. 2. The positioning of the switch arm 86 will cause the control unit 24 to exhaust the pressure cavity 38 of the pressure chamber 12. As the pressure in the pressure cavity 38 drops, the spring 76 will again extend, causing the driving diaphragm 16 to retract again to supply mode. The connecting rod 20 and injection diaphragm 18 will also retract, allowing the pump 10 to cycle again.

Although the present invention has been described with respect to specific preferred embodiments, various changes, modifications, and substitutions of parts and elements may be suggested to one skilled in the art. Consequently, the invention should not be restricted to the above embodiments and it is intended that the present invention encompass such changes, modifications, and substitutions of parts and elements without departing from the spirit and scope of the invention. 

1. An injection pump comprising: a pressure chamber having an inlet port; a driving diaphragm disposed in the pressure chamber; a fluid chamber comprising a fluid supply port connectable to a fluid source and an outlet port; an injection diaphragm disposed in the fluid chamber, a connecting rod operatively connected to the driving diaphragm and the injection diaphragm; and a control unit operatively engaged with the connecting rod and adapted to supply a pressurized fluid to the inlet port of the pressure chamber.
 2. The injection pump of claim 1 wherein the control unit comprises a mechanical switch, the mechanical switch having a switch arm operatively connected to the connecting rod, a fluid inlet adapted to receive the pressurized fluid, and a fluid supply port operatively connected to the inlet port of the pressure chamber.
 3. The injection pump of claim 2 wherein the pressurized fluid is pressurized air.
 4. The injection pump of claim 1 further comprising a biasing spring adapted to maintain the connecting rod, the driving diaphragm, and the injection diaphragm in a relaxed state.
 5. The injection pump of claim 5 wherein the biasing spring is disposed around a portion of the connecting rod and within the pressure chamber.
 6. The injection pump of claim 1 further comprising a housing having at least a first ventilation port, the connecting rod being disposed in the housing.
 7. The injection pump of claim 1 further comprising a diaphragm plate disposed between the connecting rod and the driving diaphragm, the diaphragm plated defining a working surface area of the driving diaphragm.
 8. The injection pump of claim 7 wherein a ratio of the working surface area of the driving diaphragm to a diameter of the connecting rod is 64:1.
 9. The injection pump of claim 8 wherein the connecting rod is approximately 1 inch in diameter.
 10. The injection pump of claim 1 further comprising a suction check valve, the suction check valve operably connected to the fluid supply port of the fluid chamber.
 11. The injection pump of claim 1 further comprising a discharge check valve, the discharge check valve operably connected to the outlet port of the fluid chamber.
 12. The injection pump of claim 11 further comprising a priming valve, the priming valve operably connected to the outlet port of the fluid chamber.
 13. The injection pump of claim 11 wherein the discharge check valve is further connnectable to a pressurized process.
 14. The injection pump of claim 1 wherein the fluid source comprises a source of methanol. 